A contract between a network operator and customers may offer the customer guaranteed characteristics in the telecommunications network, such as an upper limit for the packet delay and IP delay variations, which is particularly important for IP telephony and video conferencing.
Consequently, quality characteristics are guaranteed in the telecommunications network, which are made up of the unidirectional packet delay and the parameters derivable therefrom. Thus, the intention is to guarantee the customer maximum values for one or more of these parameters in the telecommunications network, for example, packet delays, IP delay variations and packet losses and/or minimum values for the throughput.
Moreover, compliance with these values must be verifiable the network operator and the customer.
Therefore, unidirectional measurement connections are established between measuring computers. On these measurement connections, measurement packets are sent from a measuring computer serving as a sender to a measuring computer serving as a receiver with a configurable distribution in time. The measurement packets contain, inter alia, time stamps and sequence numbers. To be able to measure the one-way delay, the time stamps at the measuring computer serving as a sender and the measuring computer serving as a receiver must be time-synchronized with sufficient accuracy. A technical implementation is, for example, the generation of time stamps via the GPS (Global Positioning System) receivers. This allows the time stamps to be generated with an error of ±½ μs.
The measurement results are retrieved from the measuring computers by a control computer controlling the measuring computers and stored in a database, where they are made available for visualization. The customer and the service provider need to get a prompt overview of the status of the measurement connections and of the measuring system. In this context, “prompt” means that a change in the status of the measurement connections or of the measuring system is indicated as quickly as possible. In particular, when using a plurality of measuring computers, which may also be assigned to different control computers, a large amount of information—status data—is generated. The problem here is that, due to the large amount of information, one loses track of important messages that would possibly require measures to ensure transmission quality.